Such a waterproofing membrane is known from EPS 0876532. For manufacturing the known membrane, the bituminous mass is applied to the one side of the structure to which other side a cover layer, formed by a substance, comprising a mineral or organic filler and an acrylic polymer is applied. The substance is applied as a coating to the structure before the bituminous mass is applied. The cover layer protects the membrane against exudation problems caused by ultraviolet rays. The cover layer forms as if to say a barrier against the ultraviolet rays so that the latter can not easily reach the bituminous mass. Therefore the bituminous mass keeps its waterproofing and protective properties for a longer time and substantially less oil of the bituminous mass will migrate to the upper side. In such a manner, less pollution is provoked as the oil will remain in the bituminous mass and not mix with rain water.
Although the described known membrane has improved properties for what concerns its lifecycle and the environment, the standards are changing and new constraints are or will be imposed. One of these constraints is that the membrane, when applied to a roof, must have reflective properties in order to reflect incident sunlight and cause in such a manner less heat to be absorbed by the bituminous mass and the volume covered by the waterproofing membrane. Actually reflective properties are obtained by applying a reflective coating on top of the known membrane. The drawback of applying such a coating is that it requires additional work and thus costs and that the lifetime of the thus obtained reflective layer is rather short. It is therefor needed to regularly paint the membrane surface again in order to maintain the reflective properties.